Apparatus for starting discharge lamps



June 5- 1.. w. cooK 2,379,131

APPARATUS FOR STARTING DISCHARGE LAMPS Filed Dec. 24, 1942 Inventcf: v Leonard W. Cook,

b &

His Attorney.

Patented June 26, 1945 2,379,131 APPARATUS FOR STARTING DISCHARGE LAMPS Leonard W. Cook, Strati'ord, Conn., assignor to General Electric Company, a corporation of New York Application December 24, 1942, Serial No. 420,007

9 Claims.

My invention relates to apparatus for starting discharge lamps. In my recently issued Patent 2,274,399 for Starting switch of which appara-- tus my present application discloses a further development, I described briefly the operation of an electric discharge device, such as a fluorescent lamp, the effects of continued attempts of a lamp starter such as that at present in common use to start a defective lamp, and finally a particular construction of lamp starter which would avoid maxing successive unsuccessful attempts to start such a lamp. It is the object of my present inventlon to provide improved apparatus to be employed in conjunction with a lamp starter to render the starter inoperative in the event that it is unable to start the lamp after making a reasonable number of successive attempts.

My invention will be better understood from the following description taken in connection with the accompanying drawing and its scope will be pointed out in the appended claims.

Referring to the drawing, Fig. 1' is a cross sectional view of one embodiment of my invention; Fig. 2 is a perspective view of parts of said embodiment in disassembled relation; Figs. 3, 4 and 5 are detail views drawn to a large scale; and Fig. 6 is a circuit diagram.

As shown in Fig. 1 the starting unit I which includes my present invention is mounted on a part of the lamp holder 2 extending beneath the panel or reflector 3 and the lamp 4 which it controls, the upper portion of the unit projecting through the panel into close promixity with the lamp. The starting unit comprises the base plate 6 having two propecting terminals I which terminals by engaging contacts in the lamp holder serve to retain the unit in place and to electrically connect it in circuit with the lamp in the common and well known manner. base 8 in a perpendicular manner is the insulating supporting plate 9 at one side of which is mounted the capacitor l and the lamp starting switch H which is shown by way of example as of the glow discharge tube type and on the other side of which is mounted the look-out switch 12 comprising my present invention, the two switches being connected in series between the terminals 1. The purpose of this switch is to render the starting switch inoperative after the latter has made a number of successive, unsucessful attempts to start the lamp. The starting unit is considered in the trade as being locked out".

when the lockout switch l2 opens to interrupt the circuit to the starting switch. Thereafter, the starting unit will not operate until the lockout switch is reset in a manner to be described later.

The bar I3 having its upper end l4 bent at right angles is slidably mounted on' the face of the plate 9 by the headed pins I engaging in slots in the bar. The spring l8 resiliently holds the bar in its upper or open circuit position. Ex-

Secured to the tending laterally in opposite directions from the bar is the rod l! which, as shown more clearly in Fig. 3 is curved slightly so that its outer ends bear against the face of the plate 9. The part of the rod at one side of the bar also serves as one contact of the look-out switch. The cooperating contact comprises the resilient thermal member 20 which preferably is a bimetallic strip, fixed at its lower end to the plate 9 and provided at its upper end with a latch arranged to engage the rod I1 and thereby retain the bar l3 in its lower position against the force of the spring. As

shown more clearly in Figs. 4 and 5 the latch 28 is formed by lancing the member 20 after which the end of the latch is machined off to form the rod engaging face 22 substantially parallel with the direction of movement of the latch when the thermal member is heated. By reason of the above described construction including the bar l3 and the rod H which bears at its ends on the plate 9 I am able to avoid any rocking movement of the bar on the guide pins I5 that might otherwise occur even at the expense of employing precision methods of construction which movement, magnified in the contact rod ll, would adversely affect the desired uniformity in the times of release of the look-out switch. Uniformity in the switch release operations of the latch is also improved by providing the latch with the flat rod engaging face 22 normal to movement of the latch.

Heat for operating the thermal member 20 is produced by the resistance heater 24 which preferably comprises a coil of Nichrome" wire wound ona flber gla'ss core and connected in series with one terminal I and the member 20. For insulation purposes the coil may be surrounded by a glass tube. Heat from the heater is accumulated in and transferred to the thermal member by the metal strap or clip 25 which is in good thermal relation with the heater and with the thermal member, being preferably welded to the latter. The combined thermal mass of the heater, the attaching clip and the thermal member causes a delay in the normal warping of the member which occurs as it receives heat from the heater which warping is in the direction to release the rod l1 and thereby to allow the switch to open.

The delay is proportioned to give the starting switch ample time to make several successive attempts to start the lamp unless the lamp is inoperative or for some other reason will not start.

The starting switch, the capacitor and the lockout switch described above are enclosed in the cup-like casing or can 21 which is detachably secured 'by the ears 28 to the base plate, the side wall of the casing engaging the opposite edges of the plate 9. The end head has a small central opening in which the shank of the button 29 loosely fits and is guided, its outward movement being limited by the flange 30 thereof. If the lamp is inoperative and the lock-out switch operates to open the starting switch circuit after a number of successive unsuccessful attempts have been made to start the lamp the upward movement of the part M of the bar 13 lifts the button 29 whereby it functions as a tell-ta1e indicator that the lock-out switch has operated. The defective lamp is presumably removed, the lock-out switch reset by pressing down the but-- ton and a good lamp substituted. It will be noted that the casing or can 21 is shown having a dcpressed or concave end head so that when the button is pushed up as a result of the operation of the lock-out switch it does not engage or in. teriere with the lamp. This feature is disclosed and claimed in my copending application Serial No. 470,008, filed December E l, 1M2, now Patent No. 2,352,940 issued July i, H344, and assigned to the same assignee as my present application.

What I claim as new and desire to secure by Letters Patent of the United States is:

i. In apparatus for starting an electric charge lamp, a base, an insulating supporting plate secured thereto and extending substantially perpendicular thereto, a lamp starting switch an ranged at one side thereoi, a lock-out svitch mounted thereon at opposite sides thereoi and connected in series with said starting switch, an elongated casing detachably secured to said base and enclosing said supporting plate and said starting and lock-out switches, said casing having an opening therein and a member extending through and guided by the walls of said opening, said member being arranged to engage said lock-out switch for resetting the same.

2.1m apparatus for starting an electric dis" charge lamp, a base, a cup-dike casing detachably secured to said base, an insulating supporting plate carried by said base, opposite edges of said plate being arranged to engage said casing, a starting switch at one side of said plate, a lockout switch mounted on said plate at the other side thereof, said casing being provided with a central opening therein and a tell-tale and switch restoring button having a shank slidably mounted and guided in said opening and having a flange for limiting its outward movement.

3. In apparatus for starting a fluorescent lamp including a starting switch, a switch for locking out said starting switch comprising an insulating supporting plate, a member mounted on said plate for limited longitudinal movement, resilient means for moving said member in one direction, said member having a transverse pin extending transversely from opposite sides thereof and engaging a face of said plate, a bimetallic strip aecured at one end to said-plate and having a latch at its other end arranged to engage and retain said pin when said member-is moved against said resilient means and adapted to release said pin when heated.

4. In apparatus for starting a fluorescentlamp till iii

including a starting switch, a switch for looking out said starting switch comprising an insulating supporting plate, a strip slidably mounted on one face of said plate, means for guiding said strip for movement longitudinally, a spring tending to move the strip in one direction, said strip having a pin extending transversely from opposite sides thereof and curved to engage the face of said plate at opposite ends of the pin, a bimetallic strip secured at one end to said plate and having a latch at its other end arranged to engage and retain said pin whensaid member is moved against said spring, and-a heater associated with said bimetallic strip for causing it to release the pin.

5. A thermal circuit interrupting switch comprisin an insulating supporting plate, a strip having guiding means slidably mounting it for longitudinal movement on one face of said plate, a spring between said plate and said strip, said strip having a round rod projecting laterally therefrom, a bimetallic strip secured at one end to said plate and having at the other end thereof retaining latch lanced from the strip, the free end of said latch being provided with a face for engaging said rod substantially parallel with the direction oi Luiovcmcnt of the latch when. the strip is heated and a heater for said bimetallic strip.

6. A thermal circuit interrupting switch comprising an insulating supporting plate, a strip having guiding means slidably mounting it for iongitudina1 movement on one face of said plate, a spring between said plateand said strip, said strip having a round rod projecting laterally therefrom at opposite sides thereof and engaging said face adjacent the ends of the rods, a bimetallic strip secured at one end to said plate and bent outwardly from the plate at its opposite end, said bimetallic strip adjacent said opposite end retaining latch, the e end oi said latch being provided with a face for engag izog said rod, substantially parallel with the direction of movement of the latch when the bimetallic strip heated connected in series with said bimetallic strip and arranged to heat the same.

7. In apparatus having a starting circuit for starting anelectric discharge lamp, a thermal switch lor interrupting said circuit after a numher of successive unsuccessful attempts have been made to start the lamp comprising a contact biased to open circuit position, a bimetallic strip having a latch adapted to engage and retain said contact in closed circuit position, a resistance heater, and means for supporting said heater from said strip and for accumulating heat and transmitting it to said strip comprising a metal strip having one part extending around and in good thermal relation with the heater and another part in good thermal relation with the bimetallic strip.

ll. A device for starting a discharge lamp comprising in combination a starting switch and a switch for interrupting the circuit to said starting switch comprising an insulating supporting plate,

a bimetallic strip carried by said plate and having a latch at one end thereof, a contact member movable along the surface of said plate, said contact member being normally engaged by the latch on said bimetallic contact strip but being biased for movement away from said strip when said strip is deflected by application of heat, and movable means cooperating with said contact membet for resetting it in engagement with said latch.

9. In a device for starting a discharge lamp, an insulating supporting plate, a starting switch on oneside of said plate, a lookout switch on the other side or said plate for intqrrupting the circult to sand startmg sw1th,'sa1d lockout switch LEONARD W. COOK. 

